In the manufacture of semiconductor components it is sometimes necessary to make temporary electrical connections for testing or other purposes. For example, wafer probe testing requires electrical connections with contact locations (e.g., test pads, bond pads) on a semiconductor wafer. One method for making temporary electrical connections with a semiconductor wafer is with an interconnect known as a "probe card". Typically probe cards include contacts in the form of metal probe needles. A wafer handler aligns the wafer with the probe card, and places the probe needles in electrical contact with the wafer. Test signals can then be transmitted through the probe needles to test the integrated circuits contained on the wafer.
Singulated semiconductor dice must also be tested in order to certify each die as a known good die (KGD). For testing the dice can be packaged in carriers that include interconnects having contacts for making temporary electrical connections with contact locations on the dice. Chip scale packages also require testing using interconnects adapted to make temporary electrical connections with external contact locations on the packages. For example, some chip scale packages include external contact locations in the form of solder bumps.
In making temporary electrical connections to semiconductor components, interconnects must be adapted to penetrate native oxide layers present on the contact locations. For example, aluminum bond pads on wafers and dice can include oxide layers that must be penetrated to make reliable electrical connections. Contact locations formed of solder, and other alloys, can also include native oxide layers that must be penetrated to contact the underlying metal. Another consideration in making temporary electrical connections to semiconductor components is that the interconnects preferably have compliant characteristics. This helps to prevent excessive contact forces from damaging the contact locations on the component. For example, probe needles have a natural resiliency that allows a probe card to be overdriven in the z-direction with respect to the wafer. The needles are initially placed in "touch" contact with the wafer, and then driven into the contact locations.
If interconnects do not include naturally resilient contacts, compliancy can be achieved with a mounting structure for the contacts. For example, test carriers for bare dice can include resilient biasing members that press against the interconnects or dice, and cushion the contact forces applied by the interconnect contacts. In addition to cushioning contact forces, compliancy can also be used to compensate for dimensional variations among the contact locations on a component, particularly in the z-direction.
The present invention is directed to improved interconnects having naturally resilient contacts. The interconnects can be used to construct wafer level test systems, or die level test systems, and to perform testing methods for semiconductor components.